1. Field of the Invention
The present invention relates to an optical switch for switching information transmitted by using a transmitting medium into a plurality of paths, and more particularly to an optical switch suitable for a transmitting medium of a wavelength division multiplexing (WDM) system.
2. Description of the Prior Art
There has been conventionally employed an optical transmission having an advantage that a lot of information can be transmitted at a high speed. Particularly, a wavelength division multiplexing (WDM) is a influential means because a large capacity of data can be transmitted. In the case of transmitting such a lot of data, it is efficient to selectively utilize necessary information in a receiving side, and thus required information is selected from the transmitted information by using a switching means. Further, in a digital calculator or the like utilizing an optical communication, there is a case that a plurality of communication circuits are provided and the communication circuits are selectively used by being switched. For this switching operation, an optical switch is a influential means.
Accordingly, in recent years, various kinds of optical switches have been proposed. For example, JP-A-5-249386 discloses an optical switch outputting information input from one input fiber to four output fibers. This optical switch, which directly moves an optical fiber, comprises an array constituted by two fibers and fixed in its middle portion, one fiber movably provided on one end side of the array, four fibers movably provided on another end side, and a drive means driving each of the movable fibers so as to align respective optical axes.
The optical switch described in the publication mentioned above has an advantage that it has a double switching capacity in comparison with a so-called 1xc3x972 optical switch used conventionally. However, since four movable fiber arrays are moved at a time of switching the optical switch, larger drive force is required for the driving means in comparison with the 1xc3x972 optical switch. Further, although a position of the movable optical fiber is considered a little, the consideration is not sufficient yet. In the case of moving one movable fiber, for example, there has been a risk that a front end of the fiber rotates within a switching plane, and thus the efficiency of the combination of the light is reduced.
The present invention is made by taking the problems of the conventional art mentioned above into consideration, and an object of the present invention is to realize a small-sized and compact optical switch. Another object of the present invention is to increase the efficiency of the combination by the optical switch.
In order to achieve the objects mentioned above, in accordance with an aspect of the present invention, there is provided an optical switch comprising a substrate, a first fixing member for fixing one end of an optical fiber on one end portion of the substrate, a second fixing member for fixing at least two ends of optical fibers on another end portion of the substrate, a fiber array comprising at least two optical fibers lined in parallel of which the midpoint is fixed on the substrate so that the fiber array extends between the end portions of the substrate and, and a movable device for moving an end of the fiber array with respect to the substrate.
In the aspect mentioned above, the second fixing member may fix four ends of optical fibers, the fiber array may comprise two optical fibers, and the movable device may comprise a driving device provided on each end portions of the substrate for moving respective ends of the fiber array.
Further, it is preferable that a holding member is provided on each end portion of the fiber array so as to form a parallel leaf spring structure in which the fiber array operates as an elastic body, and that the driving device moves the holding member with respect to the substrate for moving the end of the fiber array.
Furthermore, each of the first fixing member, the second fixing member and the holding members may be made of a soft magnetic material, and the movable device may be an electromagnetic actuator cooperating with the members, so that the holding members are accurately positioned with respect to the first fixing member and the second fixing member respectively.
A description will be given of some embodiments in accordance with the present invention with reference to the accompanying drawings.